1. Field of the Invention
The present invention relates to an apparatus and method for controlling data communication in a wireless local area network (LAN).
2. Background of the Related Art
FIG. 1 is a block diagram showing the configuration of a related art portable computer. As shown in FIG. 1, the portable computer, such as a notebook computer has a central processing unit (CPU) 10, a display controller 11, a bridge chipset 12, a main memory 13, a read only memory (ROM) 14, a LAN controller 15, an embedded controller 16, a battery 17, etc.
The CPU 10 and the bridge chipset 12 are interconnected via a host bus, and the bridge chipset 12, the display controller 11 and the main memory 13 are interconnected via an accelerated graphics port (AGP) bus. The ROM 14, the LAN controller 15 and the embedded controller 16 are interconnected via a system bus.
The embedded controller 16 is connected with the battery 17 via a system management (SM) bus to check the remaining power of the battery 17. The LAN controller 15 is connected with a wireless LAN card 20 of the personal computer memory card international association (PCMCIA) card type to perform data communication using a wireless LAN. The LAN controller 15, for example, may be loaded in the form of a chipset on a system board in the portable computer to perform communication.
As shown in FIG. 2, each of a plurality of stations (STAs) of the wireless LAN card is connected with a portable computer that uses the battery 17, to wirelessly transmit and receive data directly in a basic service set (BSS) network. FIG. 2 shows an independent BSS as an ad hoc network. The stations of the wireless LAN card are adapted to transmit and receive data to/from one another using predefined probe request frames.
As shown in FIG. 3, on the other hand, different BSS networks BSS1 and BSS2 are connected with a distribution system (DS) network using different access points (APs) to construct an extended service set (ESS) network. Each AP and each STA are adapted to transmit and receive data to/from each other using predefined beacon frames. As a result, a STA of the wireless LAN card connected with the portable computer can wirelessly transmit and receive data directly to/from another STA included in an associated BSS network, and also to/from an STA in another BSS network existing in the ESS network via the DS network.
As described above, the related art apparatus and method for controlling data communication in a wireless LAN has various disadvantages. The STA of the wireless LAN card, connected with the portable computer, transmits and receives data to/from another STA or AP at a predetermined high transfer speed after completing an initial setup operation for data communication therewith. In other words, because the STA of the wireless LAN card connected with the portable computer is operated at a fixed transfer speed irrespective of external environments, a large amount of power is consumed in the battery of the portable computer, which results in significant reductions in available time of the portable computer. Further, data communication time of the battery powered portable computer can be reduced.
The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.